MSE Colloquium: Farangis Ram, The Scanning Electron Microscopy-Based stored elastic and plastic deformation characterization: An Ongoing Race tied to computer vision

Postdoctoral Research Associate, Materials Science and Engineering, Carnegie Mellon University

Abstract

There is a school of thought that maintains that in a crystalline material the stored elastic strain is a crystal defect. It can be true as a defect is a deviation from the pristine periodicity of the crystal. On the other hand, in the classical texts, a crystalline defect seems to be referred to as a singularity. The fuzzy logic does not apply. A dislocation either exists or does not exist. The accumulation of defects during deformation or processing is much more stochastic than deterministic. Stored deformation is a state: it is defined by the density, character, spatial distribution, and arrangement of defects. A spatially uniform deformation state distribution is very unlikely. This is the reason that there is a race for scanning electron microscopy-based deformation characterization. In this seminar, I will introduce a SEM-based elastic strain characterization method (the cross-correlation EBSD) and a SEM-based plastic deformation characterization method (the Kikuchi Bandlet Method). I will explain their theory, their strength, their limitations and present a few of their applications.

Bio

Farangis Ram is a postdoctoral research associate at the Department of Materials Science and Engineering at Carnegie Mellon University. The focus of her work is studying the microstructural phenomena of highly deformed materials. She Received a B.Sc. (in 2005) in metallurgical engineering and a M.Sc. (in 2008) in materials design and selection, both from Sharif University of Technology, Tehran, Iran. In the year following her graduation, she won the Erasmus Mundus Grant, Partnership Agreement: 2007-‎‎0076/001 FRAME MUNB123, and embarked on a journey to Europe for a master’s program titled “Materials Science Employing Large Scale Facilities”. She studied at the University of Turin, Italy, for six months and worked at Ludwig-Maximilian University of Munich for six months. At the end of the year 2009, she started working at the Max-Planck Institute for Iron Research GmbH (MPIE) in Düsseldorf, Germany, while working towards her Ph.D., which she received from RWTH Aachen, Germany, in 2015. She joined Carnegie Mellon University as a post-doc at the end of 2015, where she has been working to date.